Acute Exposure to Normobaric Hypoxia Impairs Balance Performance in Sub-elite but Not Elite Basketball Players

Abstract

Although high and simulated altitude training has become an increasingly popular training method, no study has investigated the influence of acute hypoxic exposure on balance in team-sport athletes. Therefore, the purpose of this study was to investigate whether acute exposure to normobaric hypoxia is detrimental to balance performance in highly-trained basketball players. Nine elite and nine sub-elite male basketball players participated in a randomized, single-blinded, cross-over study. Subjects performed repeated trials of a single-leg balance test (SLBT) in an altitude chamber in normoxia (NOR; approximately sea level) with FiO₂ 20.9% and PiO₂ ranging from 146.7 to 150.4 mmHg and in normobaric hypoxia (HYP; ~3,800 m above sea level) with FiO₂ 13.0% and PiO₂ ranging from 90.9 to 94.6 mmHg. The SLBT was performed three times: 15 min after entering the environmental chamber in NOR or HYP, then two times more interspersed by 3-min rest. Peripheral oxygen saturation (SpO₂) and heart rate (HR) were recorded at four time points: after the initial 15-min rest inside the chamber and immediately after each SLBT. Across the cohort, the balance performance was 7.1% better during NOR than HYP (P < 0.01, ${\eta }_{\text{p}}^2$ = 0.58). However, the performance of the elite group was not impaired by HYP, whereas the sub-elite group performed worse in the HYP condition on both legs (DL: P = 0.02, d = 1.23; NDL: P = 0.01, d = 1.43). SpO₂ was lower in HYP than NOR (P < 0.001, ${\eta }_{\text{p}}^2$ = 0.99) with a significant decline over time during HYP. HR was higher in HYP than NOR (P = 0.04, ${\eta }_{\text{p}}^2$ = 0.25) with a significant increase over time. Acute exposure to normobaric hypoxia detrimentally affected the balance performance in sub-elite but not elite basketball players.

Keywords: high altitude training; oxygen saturation; postural control; single-leg balance test; team sports.

Figure 1

Testing protocol indicating single-leg balance tests, oxygen saturation (SpO₂), and heart rate (HR) assessment in both conditions: normobaric hypoxia (HYP) and normoxia (NOR). Hemoglobin (Hb) was assessed only in HYP. For balance trials, number of repetitions, repetition duration, and resting periods are represented as follows: leg [repetitions × repetition duration (inter-set recovery)]. DL, dominant leg; NDL, non-dominant leg.

Figure 2

Acute effects of normobaric hypoxia on a single leg balance test performance in (A) elite and (B) sub-elite basketball players. NOR, normoxic condition; HYP, normobaric hypoxic condition; D, dominant leg; ND, non-dominant leg. *Values significantly different from those obtained in NOR; P < 0.05.